Typewriter ribbon spool



3, 1965 J. F. KLOSKI 3,198,307

TYPEWRITER RIBBON SPOOL Filed Feb. 1'7, 1964 INVENTOR JOHN F. KLOSKI ATTORNEYS United States Patent 3,198,397 TYPEWRITER RIBBGN SPGGL John F. Klosiri, West Hartford, Gonn assiguor to Royal Moll-Zea Corporation, New York, N.Y., a corporation of New York Filed Feb. 17, M64, Sea. No. 345,417 4 Claims. (Cl. 197-475) This invention relates to an improved ribbon spool and more particularly to a ribbon spool having a pivoted spring biased trip lever for operating the ribbon reversing mechanism when the ribbon on the spool is substantially completely unwound therefrom; Primarily the invention is directed to an improvement of the spool disclosed in Heinrich et al., 2,880,841.

It is old in the art to spring bias a reversing trip lever on a typewriter ribbon spool toward trip or reversing position as exemplified by Brand 960,804, Myers 1,084,- 656, Hart 2,304,498 and Lambert 2,809,736. These variations of the common concept however, are characterized by structural complexities that entail added cost of material and assembly and occasionally result in malfunction in use. It will be seen that these devices, in each instance, rely on a spring comprising an element separate from the trip lever which is on lugs struck from the spool flange. It will further be seen that these exemplary spools are fabricated from sheet metal, at least insofar as the cores thereof are concerned.

A large proportion of modern ribbon spools are molded from suitable plastic materials which do not efliciently lend themselves to the trigger structure of the above mentioned patents. In view of the large number of plastic spools made and sold annually, the importance of the economic factors involved becomes selfevident. Considering Hart or Brand, for example, it is manifest that the trigger spring in each comprises a small separate element which, in itself, is not costly, but in the aggregate, represents a substantial material cost and gives rise to assembly problems.

While the plastic spool embodying the invention in the Heinrich patent has had wide commercial acceptance, it, on occasion, is prone to malfunction particularly where ribbon reversal coincides with tabulation and upon initial reversal. In many typewriters the ribbon take up spool is driven by the carriage and is accordingly rotated at relatively high r.p.m. during tabulation, the supply spool, of course, being rotated at a higher rate. I have found that when the time for ribbon reversal and tabulation coincide, the centrifugal force resulting from the high speed rotation of the supply spool prevents the re versing trip lever from falling under the influence of gravity to reversing position; accordingly, the ribbon re- Versing mechanism is not actuated and if the typist does not manually reverse the ribbon it will soon be worn through with resulting spoilage of copy.

Since the fairly recent advent of ribbon spool integrally injection molded from various plastics, certain unforesee able problems arose. One of the more serious ones, which, in past, led to the invention herein disclosed, occurred by reason of the inner convolutions of the inked ribbon, particularly a nylon ribbon, when initially wrapped on the spool core, flowing into the ,core slot between the slot edges and the edges of the vertical arm of the trip lever accommodated by the slot. It was found that after a storage period of several weeks, such inner convolutions would take a set and leave a deposit of ink that bound the trip lever arm in its slot delaying gravity release thereof to reversing position.

It is accordingly an object of the invention to provide a ribbon spool that obviates the above mentioned disadvantages.

Another object is to provide an integrally molded plastic spool provided with a metallic reversing trip lever having a self-contained spring to bias the lever toward reversing position.

Still another object is to provide a ribbon spool of the above nature that is simple and inexpensive, easy to assemble and thoroughly reliable in use. Other objects will be in part apparent and in part pointed out hereinafter.

In the drawing wherein there are shown four embodiments of the invention and wherein similar references refer to similar parts throughout the several views:

FIGURE 1 is a sectional elevation of the preferred embodiment of my invention showing the spool with ribbon wound thereon;

FIGURE 2 is a fragmentary sectional elevation showing the spool (without an upper flange) with the trip lever in reversing position;

FIGURE 3 is an isometric view of the trip lever of the spools shown in FIGURES 1 and 2;

FIGURE 4 is a top plan view, partially in section of a modified form of trip lever;

FIGURE 5 is a top plan view, partially in section, of another modification of the trip lever;

FIGURE 6 is a fragmentary elevation of a spool provided with still another modification of the trip lever;

FIGURE 7 is a fragmentary top plan view of the spool shown in FIGURE 6; and

FIGURE 8 is a fragmentary partially sectional elevation of the spool shown in FIGURES 1 and 2.

In accordance with my invention, and with reference to FIGURE 1 the ribbon spool is generally indicated at It and comprises an integral part, injection molded from a suitable plastic material, for example, and preferably polypropylene. Spool It) includes a core 11 and may include both bottom and top flanges 12 and 13, respectively, although top flange 13 may, as shown by FIGURE 2, be dispensed with in certain applications as, for example, in the well-known Twin-Pals used on certain Royal typewriters. Flange 12 is integral and coaxial with core 11 and is joined to an inner coaxial hub 14 by a plurality of radially extending flanges 15 (see FIG- URE 7), the hub being adapted to receive a spindle 16 provided with a conventional drive flange 17 by which the spool is driven to wind ribbon R thereon, the end of the ribbon being attached to the core in any wellknown manner so as not to be readily separable therefrom when the ribbon reversal occurs. For example, the wall 11a of core 11 may be slotted as at 11!) (FIG- URES l and 7) to'receive a ribbon end having a member 7% (FIGURE 1) thereon to prevent withdrawalof the ribbon from the slot when the ribbon feed is reversed.

Core wall 11a is vertically apertured opposite slot 111) to provide a slot 18, a pair of vertical posts 19 and 20 being molded integrally with the core wall along the edges of slot 18 and integrally with a shelf 21 that is integral with core wall 11 and hub, this shelf being located preferably about midway between the upper and lower ends of posts 19 and 2f), the lower ends 19a and Ella of the posts accordingly being free and capable of limited resilient deflection inwardly of slot 18 for a purpose to be described.

Extending downwardly from bottom flange 12 and integral therewith are a plurality of drive lugs 22 adapted to engage drive flange 17, a pair of upwardly open pivot pin receptacles 23 (see FIGURE 8) and an abutment post 24 (FIGURES 1 and 2). Receptacles 23 lie respectively at the opposite ends of a slot 25 formed in bottom flange 12 which slot communicates with vertical slot 18 in core 11.

Receptacles 23 and slots 18 and 25 are provided to receive a reversing lever generally indicated at 26 in FIGURE 3, this being the preferred form of lever and comprising a horizontal arm 27, a vertical arm 28 and a pair of pivot pins 29 and 30 extending laterally from the root 28a of vertical arm 28 which is narrower than the upper portion 28b of the arm for a purpose described below. Lever 26 is installed in the same manner as described in the Heinrich patent, i.e. arm 27 is inserted in slot 25 and forced downwardly therethrough until pivot pins 29 and 30 snap past the flexed lower ends of posts 19 and 26 to be received in receptacles 23. Thereafter lever 26 may pivot clockwise (FIGURE 1) or counterclockwise in accordance with the amount of ribbon R (FIGURE 1) or the lack of it (FIGURE 2) on spool core 11.

As best shown in FIGURES 1 and 3 lever arm 27 may be in the form of a horseshoe, the ends of the legs 27]) of which are integrally joined to pivot pins 29 and 30 respectively. Lever arm 27 is so formed, as by stamping from sheet metal, as to be provided with a flat spring 31 joined to the base 270 of lever arm 27 and extending toward pivots 29 and 30 between legs 27a and 27b and preferably being coplanar therewith. The root 28a of vertical lever arm is preferably coplanar with pivot pins 29 and 3t) and, as noted above is narrower than the upper portion 28b of the arm which extends upwardly from the root and preferably at a slight inclination relative thereto in the direction of arm 27. Lever 26 is stamped from sheet of suitable gauge, preferably of the order of 0.035", so that spring 31 and lever arm portion 28b will have proper flexibility for the purpose next to be described.

When ribbon R is initially installed on spool It), its inner end is suitably secured in slot 11b and the several convolutions of the ribbon thereafter machine wound about core 11. When the innermost ribbon convolution R (FIGURE 1) tightly engages lever arm 28, it swings the arm clockwise to the FIGURE 1 position causing spring 31 to flex downwardly out of the plane of arm 27 and also flexing arm portion 2% a slight amount so that arm 28 lies within slot Iii with the outer surface of the arm substantially flush with the outer surface of core 11 adjacent the edges of the slot. Accordingly, lever 26 is under a counterclockwise bias as provided by the flexing of spring 31 and arm portion 28. It follows that any deposit of ink between the side edges of arm 28 and the adjacent edges of slot 18 resulting from an extended period of storage of the loaded spool will be unable to resist such counterclockwise bias when the inner convolution R disengages lever arm 28; thus lever 26 will be snapped'to its reversing position (FIGURE 2) where its arm 27 is in position to engage a conventional reversing mechanism lever (FIGURE 1) in the well known manner. After such initial release of lever 25, the lever operates in more or less conventional manner to effect reversal of ribbon feed with one important exception, however. The effect of centrifugal force on lever 26 during tabulation was referred to above. To the end of abating such effect the inertia of lever arm 27 is lessened by the cut out portions thereof adjacent spring 31 while the inertia of lever 28 is increased by outwardly tapering arm portion 2312 so that its upper end is wider than its root end. It follows that centrifugal force will be much less likely to overcome the force of gravity on the lever when the lever is released by the ribbon to swing to its FIGURE 2 reversing position.

In the modified form of lever shown in FIGURE 4, the lever is generally indicated at 46 and comprises a resilient C-shaped horizontal arm 47 and a vertical arm 48, which is the same as arm 28 (FIGURE 3). In use of this form of lever, the abutment post 24- (FIGURE 2) depending from lower flange 12 would be displaced radially outwardly to a position where it would be engaged by portion 47a of lever arm 47. The flexing, in use, of arms 47 and 48 is the same as with lever 2'6 and the same decrease and increase of inertia of arms 47 and 48 obtains.

In the FIGURE 5 modification, the lever is generally indicated at 56 and comprises a resilient S-shaped horizontal arm 57 and a vertical arm 58 which is the same as arm 28 (FIGURE 3). In use of this form of lever, the abutment post 24 (FIGURE 2) would be located so as to be engaged by portion 57a of lever arm 57. Here again the flexing and inertial effects of arms 57 and 58 are the same as with lever 26.

In the modification shown in FIGURE 6, spool 10 is the same as shown in FIGURE 1 except that it is not provided with post 24 and is provided with a cut-out 25a extending radially outwardly from the center of slot 25. A modified form of lever, generally indicated at no includes a horizontal arm 67 and a vertical arm 68 which is the same as arm 28 of lever 26 (FIGURE 3). Arm 67 is provided with a struck down post 67a adapted to bear against the bottom of flange 12 when the lever is constrained to its FIGURE 6 position by the tightly wound convolutions of ribbon R. Such constraint results in flexing of arms 67 and 68 for the same purpose as flexing arms 2'7 and 2% of lever 26. The radial slot 25a is provided for the passage of post 67a when lever 66 is assembled to the spool, it being noted that slot 25:: is narrower than the root 6&1 of lever arm 68.

It will now appear that I have provided a ribbon spool that attains the several objects set forth above in a thoroughly practical and efficient manner.

As other embodiments of the invention are possible and as changes may be made to those disclosed, it is to be understood that the foregoing should be interpreted as illustrative and not in a limiting sense.

I claim:

I. As an article of manufacture, a molded plastic ribbon spool comprising a substantially cylindrical hollow core and an integral coaxial circular flange, said flange having a pair of spaced pivot housings formed thereon at opposite ends respectively of a trip lever receiving slot formed in said flange,

and a ribbon reversing mechanism trip lever extending through said slot and having horizontal and vertical arms and also having a pair of pivots disposed respectively in said housings to pivotally mount said lever on said spool, said horizontal lever arm comprising a pair of spaced legs each joined at one end to one of said lever pivots and connected at their other ends to a base portion, said horizontal lever arm also comprising a narrow spring member secured at one end to said base portion and lying in the space between said pair of spaced legs, said spring member extending toward but with its free end lying short of the root of said vertical arm, said vertical arm being adapted to be engaged by a ribbon wound on said spool to hold said trip lever in non-reversing position, said spring member flexibly engaging a portion of the bottom of said flange when said lever is in non-reversing position thereby to bias said lever toward reversing position; the spaces between said pair of spaced legs being provided to reduce the inertia of said horizontal arm.

2. An article of manufacture according to claim I wherein the vertical arm of said trip lever tapers outwardly from its root to its free end thereby to increase the inertia of said vertical arm.

3. An article of manufacture according to claim 1 wherein said portion of the flange bottom engaged by said spring member comprises a downwardly extending post the end of which is engaged by the free end of said spring member.

4. An article of manufacture according to claim 1 wherein said spool core has a vertical slot therein overlying said trip lever receiving slot in a position to receive 5 said vertical arm or said trip lever when the trip lever is 1,282,951 in non-reversing position. 1,475,619 2,304,498 References Cited by the Examiner 2,809,738 UNITED STATES PATENTS 5 2,880,841

510,896 12/93 Crane 16-184 929,933 8/09 Gabrielson 197-175 X 5 4 949,008 2/10 Seib 197-139 X 1,023,808 4/12 Brown 197-139 X RQBERT E 1,054,093 2/13 Davis et a1 197-139 X 10 10/18 Roebuck 197-139 11/23 Barney 197-151 12/42 Hart 197-175 10/57 Cambert 197-175 4/59 Heinrich et a1 197-175 FOREIGN PATENTS 9/44 Great Britain.

PULFREY, Primary Examiner. 

1. AS AN ARTICLE OF MANUFACTURE, A MOLDED PLASTIC RIBBON SPOOL COMPRISING A SUBSTANTIALLY CYLINDRICAL HOLLOW CORE AND AN INTEGRAL COAXIAL CIRCULAR FLANGE, SAID FLANGE HAVING A PAIR OF SPACED PIVOT HOUSINGS FORMED THEREON AT OPPOSITE ENDS RESPECTIVELY OF A TRIP LEVER RECEIVING SLOT FORMED IN SAID FLANGE, AND A RIBBON REVERSING MECHANISM TRIP LEVER EXTENDING THROUGH SAID SLOT AND HAVING HORIZONTAL AND VERTICAL ARMS AND ALSO HAVING A PAIR OF PIVOTS DISPOSED RESPECTIVELY IN SAID HOUSINGS TO PIVOTALLY MOUNT SAID LEVER ON SAID SPOOL, SAID HORIZONTAL LEVER ARM COMPRISING A PAIR OF SPACED LEGS EACH JOINED AT ONE END TO ONE OF SAID LEVER PIVOTS AND CONNECTED AT THEIR OTHER ENDS TO A BASE PORTION, SAID HORIZONTAL LEVER ARM ALSO COMPRISING A NARROW SPRING MEMBER SECURED AT ONE END TO SAID BASE PORTION AND LYING IN THE SPACE BETWEEN SAID PAIR OF SPACED LEGS, SAID SPRING MEMBER EXTENDING TOWARD BUT WITH ITS FREE 